Scanning Electron Microscope (SEM) image of Sony light-transmissive, sub-wavelength nano structures arrayed in a quasi-hexagonal lattice pattern which constitute an optical device or use in solar cells and image capture devices.
In U. S. Patent 7,633,045, Sony Corporation (Tokyo, JP) and Sony Disc & Digital Solutions Inc. (Tokyo, JP) Sony researchers detail a moth eye light transmissive optical device, a method for producing a master and replicas of the device and their use in photoelectric conversion apparatus. The nano-structures may be applied to various optical devices requiring a predetermined light transmission characteristics (anti-reflection function), such as displays, photoelectronics, optical communications, solar cells, and illuminating devices, and the like.
According to inventors Sohmei Endoh, Kazuya Hayashibe, Tooru Nagai, Ikuhiro Hideta, Shirasagi Toshihiko, Kimitaka Nishimura and Tadao Suzuki the optical devices use a translucent base material such as glass or a plastic to create material to suppress the surface reflection of light. A surface treatment of this type results in a fine, dense uneven (moth's eye) shaped surface.
In the moth eye optical device, a number of structures have higher portions or lower portions and are arranged at a fine pitch equal to or shorter than a wavelength of visible light on a surface of a base. Each of the structures is arranged to form a plurality of arc track rows on the surface of the base, and to form a quasi-hexagonal lattice pattern, and the structure has an elliptical cone or truncated elliptical cone shape having a major axis in a circumferential direction of the arc tracks. Photoelectric conversion apparatus incorporate the light-transmissive optical device at a light receiving portion of the photoelectric conversion layer.
The optical devices made by the process are applicable to ultra-fine processed structures including borosilicate glass and the like. Such a processed structure can be used in for example, a cover glass for a solid-state image capture device, such as a CCD (Charge Couple device) or CMOS (Complementary Metal-Oxide Semiconductor). Since the high transmittance is obtained in the visible light, it is considered a preferable coating to the cover glass.
FIGS. 15 and 16 are SEM photographs of the ultraviolet-cured replica substrate. The structures are arranged in a quasi-hexagonal lattice moth's eye pattern as shown in FIG. 15. Further, the structure has an elliptical cone shape. The structure with such a shape can be obtained by providing an opening in a resist mask and employing the etching step for the quartz master.
FIGS. 15 and 16 are SEM photographs of the ultraviolet-cured replica substrate. The structures are arranged in a quasi-hexagonal lattice moth's eye pattern as shown in FIG. 15. Further, the structure has an elliptical cone shape. The structure with such a shape can be obtained by providing an opening in a resist mask and employing the etching step for the quartz master.
FIG. 16 is a diagram showing a SEM photograph of a cross section of the replica substrate
